At present, as a next-generation mobile radio transmission technology, Long Term Evolution (LTE) is standardized by the 3rd Generation Partnership Project (3GPP). Moreover, as a further-advanced mobile radio transmission technology, LTE-Advanced is now under consideration. Under this consideration, in order to attain expansion of a cell coverage, that is, a communication area, and enhancement of a frequency usage efficiency, a fixed radio relay apparatus that does not move during communication is now being introduced.
In a mobile wireless communication system including a radio relay transmission function by the fixed radio relay apparatus (also referred to as relay node (RN) or relay station (RS)), as a technology for wireless connection between a radio base station apparatus (also referred to as base station (evolved Node B (eNB)), the relay node, and a radio terminal (user equipment (UE)) as a mobile station used by a user, there are two types of connection, specifically, the inband connection and the outband connection.
In the inband connection, the same frequency band as a frequency band used for direct communication between the base station and the radio terminal is used in different time periods to connect the base station and the relay node to each other. In the outband connection, a frequency band different from the frequency band used for the direct communication between the base station and the radio terminal is always used to connect the base station and the relay node to each other.
Some patent documents propose an example of the mobile wireless communication system employing such inband connection. In this mobile wireless communication system, the number of radio terminals and a radio quality (radio channel quality) in an access link and a backhaul link are collected, and in accordance with the number of radio terminals or the radio quality, allocation of an access zone and a relay zone as radio resources is determined. The access zone and the relay zone are separated from each other on the time axis, and notification of the allocation information is made for each sub-frame. In addition, as the radio quality, indexes such as a carrier to interference noise ratio (CINR), a received signal strength indicator (RSSI), and a signal to interference noise ratio (SINR) are used.
Other patent documents disclose the following scheduling technology. A data communication form in LTE is packet communication, and a resource block (RB) to be used for transmitting user data addressed to each mobile station is not determined in a fixed manner. Each mobile station measures a downlink channel reception quality (channel quality indicator (CQI)) of each resource block, and regularly reports the downlink channel reception quality to the base station. The base station determines, based on information such as a reported value of the CQI from each mobile station, a state of traffic, a property of communicated data (QoS), and information on whether or not communicated data is retransmitted data, the mobile station to which data is to be transmitted for each sub-frame.
The number of resource blocks to be used for transmitting data to each mobile station and the resource block to be used are selected in each case so that the resource block having as good a reception quality as possible is allocated. Information indicating the mobile station to which data is to be transmitted and information indicating the allocated resource block are communicated by using a control channel.
The following are related arts to the invention.    [Patent document 1] International Publication No. WO 2009/072191    [Patent document 2] International Publication No. WO 2008/096436    [Patent document 3] Japanese Patent Laid-Open Publication No. 2007-335943    [Patent document 4] Japanese Patent Laid-Open Publication No. 2008-172762    [Patent document 5] Japanese Patent Laid-Open Publication No. 2008-199579